EFFICACY AND TOXICITY OF IMMUNE CHECKPOINT INHIBITORS (ICIS) IN PATIENTS WITH METASTATIC SOLID CANCERS: A REAL-WORLD RETROSPECTIVE ANALYSIS AT A REFERENCE CENTER

Introduction: ICIs represent a revolution in cancer treatment. However, most of the evidence results from carefully selected patients (pts) included in clinical trials, and the outcomes of real world pts treated with ICI require a better characterization in terms of efficacy and safety. Objectives: This study aimed to evaluate the efficacy and toxicity of ICIs in pts treated in a real-world practice. Methods: We assembled a retrospective cohort of pts with metastatic solid tumors treated at an oncology reference center with at least one dose of ICIs (as monotherapy or in combinations), between June 2015 and June 2020. Efficacy data included overall survival (OS) and progression free survival (PFS), and were estimated using Kaplan-Meier method and logrank test. The safety profile was characterized though the incidence of toxicities overall and immune related adverse events (irAEs) and need for glucocorticoids. We conducted multivariate analyses of the efficacy and clinical and disease features. Results: We included 100 pts (median age 68.6 years). The most common tumor histologies were non-small cell lung cancer (42%) and melanoma (18%). ICIs were the first-line therapy in 32% of cases and were used in monotherapy in 73% of the cases. With a median follow-up of 14.4 months (range, 0.13-52.6), the median PFS and OS were, 10.6 months [95% confidence interval (CI), 6.25-14.95] and 27.2 months (95% CI, 15.83-38.57), respectively. 77% of the pts had toxicity of any grade (15% grade > 3). A total of 55% had irAEs of any grade (10% grade > 3). High dose steroids (>10mg prednisone or equivalent) were need in 20% of pts who had irEAs. Among the 85 pts who discontinued ICIs, 4 were due to toxicity. Fatigue (43%), rash (27%), pruritus (24%) and thyroid disorders (22%) were the most frequent toxicities. ICIs used in the first-line setting, Eastern Cooperative Oncology Group Performance Status (ECOG PS) = 0, and the occurrence of toxicity were associated with prolonged PFS in the multivariate analysis. ICIs used in the first or second-line settings and ECOG PS = 0-1 were associated with prolonged OS in the multivariate analysis. We will present data of 150 pts at the time of the meeting. Conclusions: This study based upon real-world data confirms the significant efficacy of ICIs in unselected pts with metastatic solid tumors. Efficacy outcomes were associated with ECOG PS, number of previous systemic treatments and the development of any toxicity.